1. Field of the Invention
The present invention relates to a resolver for detecting a rotational position of a rotating body, and a motor using the resolver. In particular, the present invention relates to a connecting structure between a lead wire and a terminal in the resolver, and a manufacturing method of the resolver.
2. Description of the Related Art
A resolver is a rotational position detector for detecting with a high degree of accuracy a position of a rotating body in a rotation circumferential direction. In such a resolver, a rotor rotates about a predetermined central axis to detect the position of the rotating body in accordance with a waveform of a voltage generated by a conductor wound around an armature due to electromagnetic induction.
Since the resolver is excellent in environmental resistance and is capable of detecting with high accuracy the rotational position of the rotating body, the resolver is sometimes used in a brushless motor mounted in a power steering device for assisting handling of a steering wheel in a vehicle. As various electronic devices are mounted in the vehicle due to improvement in function thereof, the brushless motor needs to occupy a smaller amount of space. Accordingly, the brushless motor needs to be reduced in size, thereby increasing a demand for a smaller resolver.
A major factor inhibiting realization of the smaller resolver is that a connecting structure between an external control circuit unit and the resolver is large. Referring to FIGS. 19 and 20, a connecting structure between a conventional resolver and a control circuit unit will be described. FIG. 19 is a cross-sectional view of an exemplary conventional resolver 100. FIG. 20 is a view partially showing a terminal block 121.
Referring to FIGS. 19 and 20, in a connecting structure between a control circuit unit (not shown) and the resolver 100, the terminal block 121 radially projecting in the resolver 100 is connected to lead wires 1213 for electrically connecting the control circuit unit and the resolver 100 to each other.
Referring to FIG. 19, the resolver 100 includes a rotor core 110 rotating about a central axis J1, and a stator 120 surrounding the rotor core 110. The stator 120 is integrally provided with the terminal block 121 radially projecting from an outer peripheral surface of the stator 120.
Referring to FIG. 20, the terminal block 121 is formed with a plurality of terminals 1211 axially penetrating the terminal block 121, a printed circuit board 1212 fixed to lower portions of the plurality of terminals 1211 by soldering, and the plurality of lead wires 1213 soldered to the printed circuit board 1212. The printed circuit board 1212 is formed with wiring patterns 1214 electrically connecting the respective plurality of terminals 1211 and the lead wires 1213 corresponding thereto to each other.
In such connecting structures, the plurality of conventional terminals 1211 and the corresponding lead wires 1213 are respectively soldered, so that a land for soldering needs to be provided for each of the connecting structures. In such a case, a distance between the adjacent terminals 1211 and a distance between the adjacent lead wires 1213 should be set equal to a sum of a width of a land 1215 and a distance between the adjacent lands 1215, and therefore, the terminal block 121 needs to be made large. As a result, the resolver 100 has not been able to be reduced in size.
In addition, since the plurality of terminals 1211 and the plurality of lead wires 1213 are soldered to the printed circuit board 1212, the resolver 100 has a structure of low reliability in which the terminals 1211 and the lead wires 1213 tend to be disconnected due to vibration, external impact, and the like.